UAD Thermionic Culture Vulture Plug-in Analysis


#1

Thermionic Culture Vulture

INTRODUCTION
For more than fifteen years, this British-made, high-gain valve unit has provided a palette of vivid distortion colours; from sublime thickening textures to demonic growls of perverted mayhem!

KEY FEATURES

  • Dial-in rich harmonic content with three diverse valve topologies
  • Subtly colour or utterly destroy existing tracks, buses, or an entire mix
    Valve Modes
    The triode and pentode settings have different saturation characteristics.
  • The ‘T’ setting generates more second order harmonics and is the cleanest, smoothest, and sweetest mode. Great for adding tube warmth to signals without obvious distortion.
  • The ‘P1’ is the most popular setting, it generates more third order harmonics and provides a harder, more edgy sound.
  • The ‘P2’ setting has a particularly aggressive sound. It can produce some of the most unusual and over-the-top effects such as frequency doubling, gating, and stuttering.
    Bias
    Modifying the bias significantly affects the saturation characteristics of the Culture Vulture. To achieve the cleanest sound, set the bias so the Meters register around 0.25-0.3mA.
    Increasing bias current will produce a thicker, rounder tone with more harmonic distortion. At higher bias currents, the cathode is over-fed and outputs rich and fat distortion.
    If bias current is decreased below 0.3mA, the unit will produce a cleaner and thinner sound. At the lowest bias settings, the cathode is starved and the signal collapses more easily, creating a gated, stuttering effect.
    Meters
    The meters of the Culture Vulture are often confused to be typical VU meters; however, the meters actually depict the current flowing through the input valves and the ‘Bias’ control adjusts this current. Current setting for lowest saturation is at 0.25-0.3mA.
    Output Stage
    An Output setting around 8-9 will provide the cleanest output. Increase this setting for higher output valve saturation.

TECHNIQUES
The ‘P1’ setting will simulate analogue tape saturation at approximately 0.4mA current reading on the meter.
Considerable distortion settings combined with filtering can modify a sine wave into a triangle or sawtooth waveform; this technique can sound very pleasing on synth bass and synth sounds.
When the input valves of the Culture Vulture are ‘starved’, the sound becomes thin and loses its body. If the bias approaches 0mA, the unit will only allow the peaks of the signal through. This has a ‘gated’ effect and sounds great on drums. Conversely, if the bias is ‘overfed’ the sound becomes fatter and more rounded.
The ‘P2’ setting reacts strangely to decreasing bias and with just the right amount of signal level will cause a frequency-doubling effect to occur. A bias of 0.15mA to 0.2mA will achieve the optimum conditions, and then all that needs to be done is to adjust the signal level until the effect is heard.

HARMONIC ANALYSIS
To analyse the non-linear behaviours of the Culture Vulture, I ran a 100 Hz sine wave through the plug-in at various settings.

100 Hz sine wave at -12 dB passed through CV T at cleanest settings (0.3mA, 8 Out)

100 Hz sine wave at -12 dB passed through CV P1 at cleanest settings (0.3mA, 8 Out)

Lol these are considered the cleanest settings, it certainly lives up to its reputation! The Culture Vulture generates strong second and third harmonics, with plenty of noise and additional low and high ordered even and odd harmonic components.

100 Hz sine wave at -12 dB passed through CV P1 Tape Emulation settings (0.4mA, 8 Out)

Very similar to the P1 cleanest setting but with stronger second and third harmonics. Hence, its richer and fatter sound!

The Culture Vulture harmonic generation and saturation is highly dependant on input level and parameter settings. I would be hear all day trying to depict this in screenshots, and it would just be confusing. Therefore, I have stuck to the cleanest settings of T and P1 and my favourite P1 at 0.4mA.

SATURATION CHARACTERISTICS
For this test I ran a synth loop through the Culture Vulture at various settings. I have compensated for level so that the synth loop peaks at -1 dBFS for maximum resolution of the waveform in Pro-L.

Dry Synth Loop

Culture Vulture T at Cleanest Settings (0.3mA, 8 Out)

Culture Vulture P1 at Cleanest Settings (0.3mA, 8 Out)

Culture Vulture P1 Tape Emulation (0.4mA, 8 Out)

Culture Vulture T Overdriven Output (0.3mA, 11 Out)

Culture Vulture P1 Overdriven Tape Emulation (0.4mA, 11 Out)

Wow, I guess a picture says a thousand words, I would not like to try and decode the saturation characteristics of this plug-in and refer to the manual: ‘The Vulture Culture captures the natural, in-between-the transients dynamic bias response inherent in the Culture Vulture’s valve-driven circuit’.

AUDIO EXAMPLES
Dry Synth Loop
Pultec Dry Synth.aif (1.3 MB)
Culture Vulture T at Cleanest Settings (0.3mA, 8 Out)
CV Cleanest T 0.3mA 8 Out Pro-L Boosted.aif (1.3 MB)
Culture Vulture P1 at Cleanest Settings (0.3mA, 8 Out)
CV Cleanest P1 0.3mA 8 Out Pro-L Boosted.aif (1.3 MB)
Culture Vulture P1 Tape Emulation Settings (0.4mA, 8 Out)
CV P1 0.4mA Tape 8 Out Pro-L Boosted.aif (1.3 MB)
Culture Vulture P1 Overdriven Tape Emulation Settings (0.4mA, 11 Out)
CV P1 0.4mA Tape 11 Overdriven Out.aif (1.3 MB)
Some Nice CV Overdrive!
CV Nicely Overdriven.aif (1.3 MB)
Culture Vulture T (+20 Overdrive 0.4mA, 8 Out)
CV T Overdrive 20 0.4mA 9.5 Out.aif (1.3 MB)
Culture Vulture P1 Tape Emulation (+20 Overdrive 0.4mA, 8 Out)
CV P1 Overdrive 20 0.4mA Tape 8 Out.aif (1.3 MB)

I really do not like the +20 Overdrive settings on the plug-in, and not to fussed about the P2 distortion either. I think the T and P1 modes have beautiful saturation properties at Drive settings below 6 but breaks up a little too much after this point, all subjective though.

FREQUENCY AND PHASE RESPONSE
Lets take a look at Culture Vulture’s frequency and phase response at various settings
What I am looking for is the frequency and phase response of the plug-in at unity and how particular settings change this relationship.
Spectrum Colours
Yellow - noise generated by the plug-in analysis software to analyse the plug-in
White - frequency response of the plug-in at that particular setting
Red - phase shift of the plug-in at that particular setting

Culture Vulture T at Unity

Culture Vulture P1 at Unity

Culture Vulture P2 at Unity

T and P1 frequency response looks how it sounds, rolling off the lower and upper frequencies. I do not like the look of them ripples in the low frequencies of P2, not an ear pleasing frequency response all round in my opinion.

Culture Vulture T at Max Drive

Culture Vulture P1 at Max Drive

Culture Vulture P2 at Max Drive

I guess this is why I dislike Drive settings above 6, I think it sounds flabby and the frequency response confirms this notion.

Culture Vulture T with +20 dB Overdrive

Culture Vulture P1 with +20 dB Overdrive

Hmmm, although I said I did not like the sound of Overdrive, I think this setting could really work nicely on the right sources. I shall not overlook this feature anymore!

Bias did not have any non-linear effect on frequency or phase response.


#2

hi paul…wow…amazing once again…and to be able to see and hear makes all of the difference.

well this is the hardware that inspired T and P settings for soundtoys decapitator. when i think culture vulture i think a few things…

  1. a DSP vulture…you got to render/bounce this thing or you won’t get too far down the road on your mix.

  2. a very squirrely gain response…using the bias is a big part of getting the distortion just right and the funny thing about this box is that the gain moves all around while you are adjusting which makes it a bit challenging to pick a sound because you have keep adjusting the monitoring to not sleep on the quieter cool sounds…

  3. very flexibe…the vulture is not just for extreme sounds – which it can do - but it can add life and an HD clean quality to things…wake sounds up but keep their own personality…

thanks again paul! please keep these coming…


#3

Well done. Thank for that.


#4

Amazing thank you very much Paul ! Thanks Danny
They need to make a special hardware to handle culture vulture dsp ^^ it’s way too greedy.


#5

Hi Danny,
Do you bounce/render as you go? I’ve found now I’m using more plugins my CPU is taking a kicking. Any advise is welcome. Thank you :slight_smile: